Abstract: A driving system for driving light-emitting modules includes driving current generation modules connected respectively to the light-emitting modules, and a brightness modulation module connected to the current generation modules and the light-emitting modules. Each driving current generation module is configured to receive signals from the brightness modulation module to control a driving current that flows through the light-emitting module it is connected to. The brightness modulation module is configured to generate the signals based on voltages provided at terminals of the light-emitting modules that are connected to the driving current generation modules.

Abstract: A driving system for driving light-emitting modules includes driving current generation modules connected respectively to the light-emitting modules, and a brightness modulation module connected to the current generation modules and the light-emitting modules. Each driving current generation module is configured to receive signals from the brightness modulation module to control a driving current that flows through the light-emitting module it is connected to. The brightness modulation module is configured to generate the signals based on voltages provided at terminals of the light-emitting modules that are connected to the driving current generation modules.

Abstract: A power supply system includes a current driver circuit, a sensor circuit, a control circuit, a voltage generator circuit and a signal generator circuit. The current driver circuit generates, based on a pulse signal, an output current for driving a load unit that includes series connected loads. The sensor circuit senses the output current to generate a sensed voltage. For each load, the control circuit is operable, based on a control input, to allow or not to allow the output current to flow through the load. The voltage generator circuit generates a reference voltage based on the control input. The signal generator circuit generates the pulse signal based on the reference voltage and the sensed voltage.

Abstract: A current driving device includes a switch, a current generator and a brightness divider. The switch is coupled between the current generator and a light emitting element, and switches between conduction and non-conduction based on a pulse signal. Based on a magnitude control signal, the current generator generates a drive current that has a magnitude related to the magnitude control signal, and that flows through the light emitting element when the switch conducts. The brightness divider is coupled to the switch and the current generator, and generates the pulse signal and the magnitude control signal based on a brightness value such that average brightness of the light emitting element is related to the brightness value.

Abstract: A power supply system includes a current driver circuit, a sensor circuit, a control circuit, a voltage generator circuit and a signal generator circuit. The current driver circuit generates, based on a pulse signal, an output current for driving a load unit that includes series connected loads. The sensor circuit senses the output current to generate a sensed voltage. For each load, the control circuit is operable, based on a control input, to allow or not to allow the output current to flow through the load. The voltage generator circuit generates a reference voltage based on the control input. The signal generator circuit generates the pulse signal based on the reference voltage and the sensed voltage.

Abstract: A voltage control device includes an output module and a control module. The output module provides an output current at an output terminal thereof based on a control voltage. The control module includes a comparing circuit, a capacitor, a charging circuit and a discharging circuit. The comparing circuit compares a to-be-compared voltage, which is associated at least with a to-be-controlled voltage at the output terminal of the output module, with a predetermined reference voltage to generate a comparison signal. The capacitor provides the control voltage. The charging circuit is operable to charge the capacitor based on the comparison signal. The discharging circuit is operable to discharge the capacitor based on the comparison signal.

Abstract: A voltage control device includes an output module and a control module. The output module provides an output current at an output terminal thereof based on a control voltage. The control module includes a comparing circuit, a capacitor, a charging circuit and a discharging circuit. The comparing circuit compares a to-be-compared voltage, which is associated at least with a to-be-controlled voltage at the output terminal of the output module, with a predetermined reference voltage to generate a comparison signal. The capacitor provides the control voltage. The charging circuit is operable to charge the capacitor based on the comparison signal. The discharging circuit is operable to discharge the capacitor based on the comparison signal.

Abstract: The present invention provides a circuit of reducing electro-magnetic interference for a power converter. The circuit includes an oscillator, a switching voltage divider, and a sample-and-hold circuit. The oscillator has a terminal for receiving a modulation voltage. The modulation voltage is correlated with an input voltage obtained from an input of the power converter. The switching voltage divider is enabled and disabled by a switch to attenuate the input voltage into a sampled voltage in response to a sampling signal. The sample-and-hold circuit receives the sampled voltage to generate the modulation voltage. A switch of the sample-and-hold circuit controlled by a holding signal conducts the sampled voltage to a capacitor of the sample-and-hold circuit to generate the modulation voltage across the capacitor.

Abstract: The present invention provides a circuit of reducing electro-magnetic interference for a power converter. The circuit includes an oscillator, a switching voltage divider, and a sample-and-hold circuit. The oscillator has a terminal for receiving a modulation voltage. The modulation voltage is correlated with an input voltage obtained from an input of the power converter. The switching voltage divider is enabled and disabled by a switch to attenuate the input voltage into a sampled voltage in response to a sampling signal. The sample-and-hold circuit receives the sampled voltage to generate the modulation voltage. A switch of the sample-and-hold circuit controlled by a holding signal conducts the sampled voltage to a capacitor of the sample-and-hold circuit to generate the modulation voltage across the capacitor.

Abstract: The present invention provides a circuit of reducing electro-magnetic interference for a power converter. The circuit includes an oscillator, a current generation circuit, a feedback circuit and a ramping generator. The oscillator has a first terminal for receiving a first jittering current and a second terminal for feeding a second jittering current. The first jittering current and the second jittering current are correlated with a line signal obtained from an input of the power converter to vary a frequency of the oscillator. The first jittering current and the second jittering current are unequal. As the first jittering current is set greater than the second jittering current, the frequency of the switching signal increases whenever the line signal is increasing. As the first jittering current is set lower than the second jittering current, the frequency of the switching signal decreases whenever the line signal is increasing.

Abstract: A switching controller for a PFC converter is provided. The switching controller comprises a switching-control circuit, a current-command circuit, a programmable feedback circuit, a modulator, an over-voltage detection circuit, and a light-load detection circuit. The switching controller is capable of regulating a bulk voltage of the PFC converter at different levels in response to load conditions of the PFC converter. A turbo current eliminates a first voltage undershooting of the bulk voltage at the transient that the bulk voltage decreases to arrive at a second level from a first level. A voltage-loop error signal is maximized to eliminate a second voltage undershooting of the bulk voltage at the transient that the bulk voltage starts to increase toward the first level from the second level.

Abstract: A switching controller for a boost power converter includes a switching-control circuit and a programmable feedback circuit. The programmable feedback circuit is coupled to an output of the boost power converter via a voltage divider. The programmable feedback circuit includes a current source coupled to a switch. On a light-load condition, a power-saving signal turns on the switch. The switch will conduct a programming current supplied by the current source toward the voltage divider. Furthermore, the voltage divider is externally adjustable for programming a determined level of an output voltage of the boost power converter on the light-load condition. Additionally the present invention increases system design flexibility to meet practical power-saving requirements without adding circuitries and increasing cost.

Abstract: A switching controller for a boost power converter includes a switching-control circuit and a programmable feedback circuit. The programmable feedback circuit is coupled to an output of the boost power converter via a voltage divider. The programmable feedback circuit includes a current source coupled to a switch. On a light-load condition, a power-saving signal turns on the switch. The switch will conduct a programming current supplied by the current source toward the voltage divider. Furthermore, the voltage divider is externally adjustable for programming a determined level of an output voltage of the boost power converter on the light-load condition. Additionally the present invention increases system design flexibility to meet practical power-saving requirements without adding circuitries and increasing cost.